In laundry dryers, and particularly laundry dryers used in commercial environments, it is desirable to dry laundered items to different degrees of remaining moisture content depending upon the nature and application of the items being dried. For example, in hotel operations, it is common to dry towels to a point where they exhibit little or no remaining moisture. On the other hand, when drying sheets and other linens, it is often more efficient to stop the drying operation when the items still have a higher degree of remaining moisture content in order to facilitate subsequent ironing or finishing of the item prior to reuse.
In a clothes dryer equipped with moisture sensing controls, the dryer's electronic control may monitor the moisture level in the laundered garment, and terminate the drying cycle when the moisture sensing input indicates to the control that the garments are at the desired final moisture content. The operator of the clothes dryer must typically instruct the electronic control what the target final moisture content should be for a particular load of garments. This is done by programming the electronic control with a parameter value which is the desired final moisture content for the load of garments. This desired final moisture content value may be a specific numerical value for the percent moisture remaining in the garment load, such as “5% final moisture content.” Alternatively, the value may be a more qualitative value such as “Damp,” “Dry,” or “Overdry” which defines the final moisture content in more general terms.
In many cases, however, the operator of the clothes dryer is not able to specify what the final moisture content should be. In some cases the operator of the clothes dryer may need to physically touch the garments to determine whether they are dry enough for the operator to stop the drying cycle. In other words, the operator may not know what various specific numerical percentages of moisture content feel like, but if the garments “feel” dry enough to the touch, then the operator knows to stop the drying cycle.
If the garments still feel too damp, the operator may then continue the drying cycle and periodically check the garments. By trial and error, the operator may eventually acquire a feel for what percentages correlate to which physical feel, and may thus become more adept at setting values for final moisture content.
Moreover, many different variables also affect the ability of the electronic control of the dryer to accurately detect the final moisture content of the items being dried: the ambient temperature and humidity, variations in the material type of garments in the load, a mixture of different garment material types in the load, variations in the electrical input power to the machine, and variations in the load sizes. Any of these variables may result in the electronic control not being able to dry the garment load to the desired final moisture content as specified by the user. Heretofore it has been difficult to alter or modify the control to compensate for such further variable conditions.
Moreover, if the moisture sensing input is not working properly, the electronic control will not be able to sense the moisture content of the garments. A number of factors could affect the quality of the signal at the moisture sensing input: wiring or electrical connections which have become broken, disconnected or shorted, a buildup of residue or contaminant on the cylinder and baffles preventing accurate sensing of the load moisture content, drifting of a moisture sensor device, and/or a complete or partial failure of the electronic control. When inconsistent results for particular drying settings occur, it has been difficult for the user to easily determine whether the dryer control is functioning properly without extensive or cumbersome disassembly of the dryer and its controls.